Means for determining altitude



Feb. 26, 1929.

K. H. BEL] MEAfiS FOR DETERMINING ALTITUDE 1927 4 Sheets-Sheet Filed F STAR. OR PLAN ET y m .G/

w 0 m H 4 L P m w Feb.26, 1929. 1,703,105

. K. H. BEIJ mums FOR DETERMINING ALTITUDE Filed Feb. 28, 1927 4 Sheets-Sheet 2 AARL H/LD/NG BE/J,

' lNVENTOR BY ATTORNEY Feb. 26, 1929.

K. H. BEIJ MEANS FOR DETERMINING ALTITUDE Filed Feb. 28, 1927 4 Sheets-Sheet KAR H/LD/NG BEIJ,

ATTORNEY K. H. BEIJ MEANS FOR DETERMINING ALTITUDE Feb. 26, 1929. 1,703,705

Filed Feb. 28, 1927 4 Sheets-Sheet 4 K4 in. H/LD/NG BEN. 55 mvewron gym M BY ATTORNEY 14 that includes lenses 15 and 16, prisms .larly to a sextant of tion partly in section,

section of 30 F menial eb. 26, 192 1 UNITED STATES PATENT OFFICE. mar. 11. mm, or wasnmeron, msrnrcrox commit;

were]; nnr mummeurnuna Application filed February 28, 1927. Serial in. 171,600.

tending through the plate 10, and on which is mounted a segment. 23 having a serrated arc. A knurled thumb wheel 24 tioned that it is easily operated leasing hold of the h secured to it a gear 25 that engages with a smaller gear 26 mounted on a shaft 27. Motion istransmitted by this shaft to shaft 28 through bevel .gears29 and 30. A worm gear 31 secured to shaft 28 engages with the serrated arc of the segment causing the angular relation of the index mirror to change by operation of the thumb wheel 24. The ratio of gearing may be turn 'ofthe thumb wheel corresponds to two revolutions of the worm gear and one new-- lution of the worm ear moves theindex mirror one degree. of the index mirror corresponds to two degrees of altitude, thuscone revolution of the Reference is to be had to the accompanyworm gear gives a two degree altitude ing drawings forming part of this specifichange to the mirror. cation. in which like reference characters inl' dicate-corresponding parts throughout the several views, and in which:

Figure 1 is a side M invention relates broadly .to a means for determining altitude and more particuthe bubble type.

An object of the invention is to provide a device of the character described with means for setting, locking in position, and indicating the angular relation of sun glasses with respect to the horizon.

- Another object is to provide a sextant having means for simultaneously adjusting and recording the angular relation of an'findex mirror with respect to the horizon. A further object is to provide a sextant in which the sun glasses and index mirror may be adjusted without releasing hold of the handgrips of the instrument.

'With the above objects in view the invention consis sin the construction, combination and arrangement of parts as will be hereinafter more fully described.

without re- Inay used equally as well. Shaft 28 also operates a registering device '32, that ma be of any desired type, suitably calibrate The sun glasses 13, for the purpose of dimming th beswung over the index using the instrument in to be interposed in the sun between the mirror elevation of my inven- Figure 2 is a central vertical longitudinal Figure 1, 4 igure 3 is a view of the SldGCOPPOSitG to that shown in Figure 1,

Figure 4'is a front view, a Figure 5 is a detail plan view of the dual setting an recording mechanism of the index mirror,

Figure 6 is a view on the line 66 of, Figure 5,

Figure 7 is a detail of the recording gauge for the index mirror, and

Figure 8 is a View on the line 8-8 of igure 7. 7

Referring more particularly to the drawings, 10 and 11 are a pair of parallel side plates between which are positioned the index mirror 12, sun glasses 13, and telescope the daytime, so direct rays of ale and the sun, The

The member 33 is mounted on A knob 37, slidably carried by the shaft 34 and secured thereto by a key 57 passing through the shaft, and o erable in slots 58 in the knob, regulates te angular adjustment of the sun glasses. to the knob engages with 38 carried by the side plate 10 to maintain the glasses in the desired angular adjust- 17 and 18, and a levellin bubble 19. Hand ment. Spring 39, under tension, holds the grips 20 and 21 are provided on the exterior knob in its innermost position effecting enof the plates.

gagement of the pin 36 with the toothed The index mirror. 12 is a strip of unsilmember 38. There is a pointer 40 on the vered optical glass with paralled upper and knob to indicate the position OI the sun lower polished surfaces. A piece of optical glasses according to graduations 41 on the glass thus prepared 'will reflect objects at the plate 10, stop pins 42 and 43 limiting its same time that it permits objects to be viewed movement to 90 degrees. Spring clips 44 through it. It is mounted on a shaft 22 having bearings in the side plates and ex-- a toothed membersuch that one I do not desire to imit myself to this precise ratio, as others e image of the sun, are adapted.

mirror, when pinion 55 that is connected to shaft 34 by arms 35;

A pin 36 secured,

1s so posiand grip 21 and has ne degree of motion against the tension the bubble 19 which 16 through the This assembly permits of the rapid adjustment of the sun mate altitude of t only necessary to lasses, for, the approxie sun being known, it is pull out the knob 37 of the spring 39, turn it until the pointer 40 points to' the approximate altitude of the sun on the graduations 41. The knob is then released, engaging in the toothed member 38 holds the glasses in the desiredposition. It is to be noted that this can be done with the thumb and forefinger of the left hand without releasing the grip, of that hand on the handgrip 20.

When using the instrument during the day, suflicient light is admitted through the telescope openi g to illuminate the bubble but at nightartificial light is required. I, therefore, mount an electric light assembly 48, slidable fore and aft, so that its rays may be concentrated on the bubble, its intensity of illumination being controlled by a rheostat 49 located at the upper end of the hand grip 20 in which is placed a battery for the source of current. The rheostat is controlled by knob 50.

A means 51 for illuminating the index mirror registering device 32 is located inside the thumb wheel 24, as may be more clearly seen in Figure 6, and is controlled by a switch 52 in the bottom of the hand grip 21 in which is placed the battery for this lamp. A reflector 53 concentrates the light on the registering device.

A removable threaded cap 54 holds an auxiliary shaded or colored disk for darkening the, interior of the instrument when used in extremely bright sunlight.

I also provide a bracket 56 secured to the housing between the hand grips for holding a stop watch for recording the exact time of taking a bearing.

In operating the instrument in the day time, the observers eye is placed approximately at the point marked A in Fig. 2, so that he looks downwardly at an angle at the index mirror 12 and sees the sun reflected therein, dimmed by the sun glasses if desired. Simultaneously he sees the image 0 is projected by the lens index mirror 12. The images of the bubble and sun should coincide on the index mirror before an accurate reading is obtained. They are'brought into coincidence by a careful adjustment of the index mirror by means of the thumb wheel 24. Heretofore in instruments of this character, the sunglasses have been so positioned that they come between the observers eye and the index mirror. This not only dims the image of the sun, but also greatly dims the clearness of the image of the bubble, which would lead to the obtaining of an inaccurate reading. In the' arrangement of erable to place the eye underthe pin 36 length of of celluloid the sunglasses hereinabove described, the observer'has an open unrestricted view of the index mirror, yetthe image of the sun is sufiiciently shaded to cause no inconvenience to the observer. At night time when sighting on one of the lesser luminaries, it is prefthe index mirror at approximately the position marked B in Fig. 2, upwardly through the directly at then adjusted'by means of the'thumb wheel 24 until the image of the bubble is reflected in the mirror to coincide with the luminary as viewed through the index mirror. The lens 16 is a collimating lens. The bubble 19 is in the focal plane of the lens 16, and the radius of curvature of the upper lens 56 of the bubble horizon is made equal to the focal the lens 16. The bubble is thus optically at infinity and the coincidence setting may be made at any point of thefield as long as the bubble does not touch the sides of the container. In this way no centering cross wires are needed. If a natural horizon is available, the bubble may be disregarded and the horizon viewed directly through'the telescope 14.

It will be understood that the above description and accompanying drawings comprehend only the general and preferred embodiment of myinvention and that various changes in minor details of construction, proportion and arrangement of parts may be resorted to within the scope of the appended claims and Without sacrificing any of the advantages of my invention.

What I claim is- 1. A bubble sextant including in combination a frame, hand gripsarranged on either side of the frame, illuminating members mounted on the grips, an index mirror pivotally mounted in the frame, means for pivoting and determining the angular adjustment of the mirror, a curved bubble container, a collimating lens having a focal length equal to the radius of the curvature of the container and situated between the index mirror and the container, a shaft within the frame, blocks provided with notches secured to the shaft, a plurality of sun glasses mounted on the shaft, clips car- 7 index mirror and the luminary. The mirror 18 ried by the sunglasses engageable with the the observer looking mina ting members carried by 2. A bubble sextant including in combination a frame, hand grips on the frame, illuthe grips, an index mirror adjustably mounted in the frame, means for adjusting and determining the angular position of the mirror, a curved bubble container, a collimating lens between the index mirror and container, adjustable sunglasses mounted in the frame 10 and adapted to be interposed singly or as a unit between a luminary and the index mirror, means for maintaining the sunglasses in angular relation with respect to each other, retractible means for pivoting the glasses within the frame and determining their angular position with respect to the mirror, and means within the grips for energizing the illuminating members.

KARL H. BEIJ. 

